Is Optical Media dead?

[wblock@]

No. If even one out of 160 DVDs fails, the backup is gone. Chances this happens are considerably higher then the USB external drive failing.

And if even one spot on the hard drive fails, that backup is gone. The question is which is more likely, and I don't have numbers either way. Personally, I can't recall ever having a DVD fail. I did have a brand-new hard drive fail last week, though.

 

[gkontos]

Actually, I usually see a greater compression ratio. But okay, if we say 160 DVDs at $0.20 each, that's $80. About the same price as a (cheap) USB drive.

Let's make them double layer. Let's even assume that you get them at the same price. So, that would be 80 DVDs. Lets even say that with compression you manage to get them to 70 DVDs.

Even then, you would need to hire someone full time just to swap DVDs.

Hard to say on that one. The USB drive has fragile platters, motors, and electronics. Without actual statistics, I don't know.

Sure but again simple math. 70 points of failure or 1

Now... what if you don't have 750G of data to back up? What if you have varying amounts, say anywhere from 1G to 110G from various machines, and want to keep archival copies?

I intentionally exaggerated for the shake of the argument. But again I don't believe that optical media is cheaper for backup solutions.

The big picture is that when you backup data, you need to somehow be able to archive and index them. Why? Because the most important factor in a backup strategy is the ability to restore in a timely manner while keeping the costs down.

Respectfully always.

 

[kpa]

I use an external USB disk with a ZFS pool that has copies set to 2 as my back up media. If one sector goes bad the data is still fully recoverable.

 

[wblock@]

Let's make them double layer. Let's even assume that you get them at the same price. So, that would be 80 DVDs. Lets even say that with compression you manage to get them to 70 DVDs.

Even then, you would need to hire someone full time just to swap DVDs.

Ah, but part of my scheme is using multiple DVD drives (six at present). I think the most swaps I've done so far are three.

Sure but again simple math. 70 points of failure or 1

Certainly it's not that simple. 70 slabs of inert plastic whose major enemy is sunlight versus a hard drive with moving parts and RoHS solder, whose main predators are electricity, temperature, G-shock, and, arguably, cost reduction.

I intentionally exaggerated for the shake of the argument. But again I don't believe that optical media is cheaper for backup solutions.

I can agree with that. Per gigabyte, DVDs are about the same cost as inexpensive hard drives. But you don't have to buy or use 500G at a time, and they can be separated. Dual-layer or even Blueray have advantages, but the drives are far less common. I like the idea of backups that can be read on any available machine, even if it's not running FreeBSD.

The big picture is that when you backup data, you need to somehow be able to archive and index them. Why? Because the most important factor in a backup strategy is the ability to restore in a timely manner while keeping the costs down.

Right, but that is driven by the kind of backup. These DVDs tend to be emergency backups, images of machines to be restored in the case of hard drive failure, fire, flood, theft, that kind of thing. Secondary backup. For primary backup, I have a ZFS RAID setup. The combination of these two is an attempt to provide quick backup along with offsite archival copies without the expense of external drives or tape.

 

[fonz]

I for one am not going to backup 2 TB with DVDs. I'll take my chances with external USB hard drives and use other media (DVD and USB flash drive) as a second backup for the really important data.

Fonz

P.S. Unfortunately I'm apparently not real enough a man to do what Linus Torvalds claims to do: "Real men just upload their important stuff on ftp, and let the rest of the world mirror it "

[size="-2"]DISCLAIMER: The smiley comes from the quote itself. I wouldn't dare trying to be funny on my own accord, that would probably just get me reported for vulgar, childish, unprofessional and inappropriate humour. Please don't complain.[/size]

 

[bsduser35325]

Hard drives tend to last very long. I have old PCs that bang and shake and they still work as long as its properly secure. Backing up more than 100G of data with DVD is just silly you would have to organize and label them. Hard drives are so cheap you can get a few TB under $150.

DVD is a lot slower too.

 

[kpa]

P.S. Unfortunately I'm apparently not real enough a man to do what Linus Torvalds claims to do: "Real men just upload their important stuff on ftp, and let the rest of the world mirror it "

The more recent version of that scheme would to create a torrent out of your important data. Encrypt it first and publish it with a promise of a price in case someone can crack the encryption.

 

[recluce]

I would never trust my backups to DVD-R (DVD-R used to include DVD+R). Experience has taught me that not all DVD media age well. While using high quality media helps, you will have a hard time reliably purchasing "high quality". The brand name DVD-R may have the same box now and six months from now, but the media itself may be completely different. Quality white label media, like Taio Yuden, is often counterfeit by some fly by night operations, so it may be even more "hit or miss". This disqualifies DVD-R as an archive media in my opinion, I just had too many media go bad over time.

The alternatives:

1.) "naked" hard drives used in an external eSATA dock - light years ahead in transfer speed and reliability compared to DVDs. SMART monitoring gives at least some assurance about drive health.

2.) DVD-RAM. Old fashioned and slow as hell, but highly reliable. I have yet to see a DVD-RAM media that fail on READ (they may fail during write), DVD-RAM low-level read-verifies while writing.

3.) USB thumb drives may be an adequate replacement for DVD-RAM - or not. I had USB sticks fail on me and SD cards too, mostly without any rhyme or reason.

My strategy: all data is held in a raidz2 ZFS pool, with a copy on external hard drives that are not usually connected to the server (but stored in an archive box). The most important data gets an additional copy on DVD-RAM.

As to hard drive handling for backup drives: I use only drives that have had at least a 1000 hour burn-in and are no older than 6 to 7 years at the most. Drives are started up and run for about 24 hours at least once every 3 months, with conveyance and extended SMART tests.

Using these precautions, I have yet to see a quality drive (I don't use low-cost "green" drives) to go bad on me. The 1000 hour burn-in takes care of "infant deaths" and the 6 to 7 year limit reduces the risk from aging components. (I have just started to retire 500GB WD Black that exceed the 6 year limit).

 

[Savagedlight]

My current backup scheme:
- ZFS send/recv to an external harddrive. There's three hard drives which are used, on rotation. Stored in a fireproof safe on-site.
- ZFS send/recv important (i.e. user-generated) data to an off-site server
- File copy of important data (really important user-generated data; such as databases) to dual-layer Blu-Ray disk. Stored in a fireproof safe off-site.
Optimally, I should have some tape backup tossed in there somewhere, but this is for my home system, so I can't justify that expense.

It's not a question of optical media being dead, because it's not. It's more a question about when it's appropriate to use it.

As for all the previous posts about "if only one of the 80 DVDs failed, your entire backup would be dead": Only if you're doing it wrong. You should backup in such a way that each DVD would contain a part of the data set, so if one dvd goes lost, the remaining DVDs are still accessible. The same argument goes for backup to a hard drive; If a sector is dead and data is unrecoverable, that shouldn't kill your entire backup.

If you have a single type of backup, and think it's enough; think again.

 

[Pushrod]

I for one am not going to backup 2 TB with DVDs. I'll take my chances with external USB hard drives and use other media (DVD and USB flash drive) as a second backup for the really important data.

In my experience, USB external hard drives have a 100% failure rate. Every single solitary USB drive that I or a friend has owned, has had controller issues and has caused writes to fail and the device to become unresponsive. I would never put anything other than music or something else unimportant on one.

 

[fonz]

In my experience, USB external hard drives have a 100% failure rate. Every single solitary USB drive that I or a friend has owned, has had controller issues and has caused writes to fail and the device to become unresponsive.

I'm sorry to hear that. However, I myself have yet to have a single problem with any external USB hard drive I own - even while some of them have seen quite a bit of travelling - and none of my friends/relatives have so far reported any such problems either. Classic case of YMMV, perhaps?

Fonz

 

[gkontos]

Guys wake up please. We are living in a world where we daily consume Terabytes of data. Our storage needs have grown so much during the last 5 years.

I see people daily having to deal with 8-12 TB of data on their storage boxes. That data need to be backed up daily and believe me there is no optical media that can ever handle this amount of data.

 

[wblock@]

Therefore, even if you only have 20G to back up, ignore optical? There does not have to be a one-size-fits-all solution.

 

[gkontos]

Therefore, even if you only have 20G to back up, ignore optical? There does not have to be a one-size-fits-all solution.

See how you limit the size of data. But still, having to organize all those disks ...

 

[wblock@]

That's the point, that people have different amounts of data to back up. Not everybody has 2TB to back up, and those who do will probably have to use a different system than those who have 20G. That's not an imaginary figure; I actually do have multiple "small" systems to back up. In the world in general, they are more common than multi-terabyte archives.

20G, incidentally, is only three or four DVDs due to compression. Not a terrible hardship to organize.

 

[bsduser35325]

Flash drives are still better if backups are anything below 200G. They are smaller and faster. We already got USB 3.0. DVDs are oudated.

 

[Savagedlight]

Flash drives are still better if backups are anything below 200G. They are smaller and faster. We already got USB 3.0. DVDs are oudated.

Better how? Are they cheaper per GB? Easier to physically store? Easier to destroy when no longer needed? More resistant to magnetic fields?

I find it more practical to keep 12 dual-layer blu-ray disks (50GB per disk; 1 disk per month) for a year, than to cycle 12 SSDs for the same purpose. And as I've already posted earlier in the thread: You really should backup your stuff to several different types of media.

 

[wblock@]

Media       $/Gigabyte   Size         Write speed
-------------------------------------------------
DVD             0.045    4.4G         10M/sec
BD-R            0.036    25G          17M/sec*
BD-R DL         0.093    50G          18M/sec*
Hard disk       0.050    500G+        20-120M/sec
SSD             0.800    32-512G      20-400M/sec
Flash drive     0.500    up to 64G    2-10M/sec

For reference. The DVD write speed is average, I have some drives that consistently get 12M/sec, some that only do 8M/sec. Don't have a BD drive to get an actual speed, hence the star. Some flash drives are faster, but not the ones that cost $0.50 per gig. And remember that if you are keeping archives, the media is not reusable.

There's a column that's missing, which would be reliability. I don't have any hard numbers for that, but would be interested if others do.

 

[wblock@]

I find it more practical to keep 12 dual-layer blu-ray disks

That is something I have not tried. Does the normal DVD burning software available on FreeBSD like growisofs(1) and cdrecord(1) work to write BD disks?
Do you have an idea of what sort of actual data transfer rates it achieves?

One downside is that not every machine around can read one of those disks, unlike single-layer DVD. But the capacity is tempting.

 

[ch]

Considering the fact that I'm one of the poor and that I'm without a place to live, whatever I'm able to find will be used.

For those of us with very little, optical media will be used for quite a while. The "media" which states such- "CDs/DVDs/etc are dead."- is composed mostly of those who have not to struggle.

If I'm looking about and find a computer which uses a cassette tape or
eight inch disk- and that the media is available and working- I'm going to use it.

I beg to differ. I have no money for CDs, and using my flash drive fifty times is a lot more economical than paying for an optical drive in a computer or buying CDs. I started using USB when I got my cheap computer, and it became even more necessary once I was living in a restaurant building and had no space for wasted CDs.

 

[Pushrod]

So, what we can conclude is that optical media are suitable for backups when you have any of the following:

-Incremental archives (and keeping them all)
-Backing up a small amount of data
-Personal preference
-Large amounts of free time

 

[TiberiusDuval]

For small amount of data (<100 gigs for DVD's) why not? Optical media is durable when stored well, is quite compatible and so on. I had most of my mp3 collection and some personal files, PGP keys and like backed up on CD-roms- Nowadays I have multiple computers where data that is not easily available from net is backed up.

I don't know for sure how long data will reliably last on cd-r's or dvd-r's but I think they will certainly be more reliable than magnetic 3,5" floppies. And regarding floppies just took out couple of months ago my Amiga 500 from storage, tested my disk collection and most of floppies used with it are still in working condition and show no noticeable data loss, quite many of those diskettes are over 20 years old.

 

[throAU]

Let's make them double layer. Let's even assume that you get them at the same price. So, that would be 80 DVDs. Lets even say that with compression you manage to get them to 70 DVDs.

To be fair, if you're serious about storing bulk data on optical media, you'd be using 40-50GB BD these days. rather than DVD.

But yes, if you have any significant quantity of data, retrieval and indexing is so much easier with hard drives. Backup and restore speed is so much faster.

 

[kpa]

How is redundancy best handled on DVDs or BDs? As noted before the backup may be lost completely even if one block is unreadable. There must be solutions to this problem?

 

[TiberiusDuval]

What if you do not compress files but burn them as they are, that way only file or two may be lost if there is some bad blocks.